Mr. Yoshi has 75 papers. He graded 60 papers, and he had a student grade the rest. What percent of the papers did each person grade?

Question

Our teacher says we have to use a double number line.

Answer 1

Mr. Yoshi graded 60 out of 75 papers.  Percentages are the ratio of a portion to the whole, so Mr. Yoshi graded:

     60/75 = 4/5 or 80% of the papers.

 

Now, we could subtract:  100% - 80% = 20%, but let's calculate:

  the student graded 75-60 = 15 of the papers.

     15/75 = 1/5  = 20% of the papers.